Effect of cilnidipine on insulin sensitivity in patients with essential hypertension

Abstract

To clarify the effect of cilnidipine, a long-acting dihydropyridine Ca-antagonist that blocks both L- and N-type Ca2+-channels, on insulin sensitivity, cilnidipine at 5 to 10 mg/day was administered to ten patients with essential hypertension for 12 weeks. Mean age and body mass index (BMI) were 57.7±5.0 (SEM) years old and 27.1±1.5, respectively. Blood pressure, serum levels of catecholamines, glucose and lipid were determined before and after the treatment. Insulin sensitivity was also measured by a euglycemic hyperinsulinemic clamp method using an artificial pancreas (STG-22; Nikiso, Tokyo, Japan) before and after the treatment. Cilnidipine administration significantly lowered blood pressure from 154/96 to 137/84mmHg (p<0.05). The glucose infusion rate was significantly increased by 20.8%, from 3.27±0.36 to 3.95±0.55 mg/kg/min (p<0.05). HbA1c and serum lipid levels such as total cholesterol and triglyceride were not altered. In addition, clinidipine treatment did not significantly increase serum norepinephrine levels (278±25.2 vs. 332± 33.6 pg/ml). Our results suggest that cilnidipine improves insulin sensitivity, possibly due to its exerting a vasodilatory action without stimulating sympathetic nervous activity.